Our increasingly mobile and mechanized society uses a variety of different fuels (e.g., gasoline, diesel fuel, ethanol, etc.) as energy. Liquid fuels are generally stored in liquid reservoirs such as underground storage tanks, above ground tanks, or any of a variety of different containers. Typically, liquid fuel reservoirs have inlets and outlets through which fuel can be added to and/or removed from the reservoir. These inlets and outlets may typically consist of a riser pipe extending from the reservoir. Internal to the riser pipe is a drop tube and the space between the riser pipe and the drop tube is frequently referred to as the interstitial space between the riser pipe and the drop tube. The riser pipe is typically threaded to an adapter collar to which a fuel line can be coupled. A spill container surrounds the fill adapter collar and acts as a secondary containment system for any overflow or spillage that may occur during the filling process.
Such configurations have proven to be very effective, however, the interstitial space between the riser pipe and the drop tube can allow an excessive amount of vapor to be introduced into the atmosphere, especially during the filling process. For example, the interstitial space can act as a chimney for vapor to be released from the ullage of the tank. Though the interstitial space area is relatively small, because of this chimney effect, the vapor from the entire ullage area of the reservoir can be released through the interstitial space and may therefore create an environmental concern. As exemplified by the disclosure of U.S. Pat. No. 6,523,581, there is a continuing desire to provide apparatus and methods for minimizing, such as preventing, release of vapors from an ullage area of the reservoir.